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Interdependence among non-metric traits as well as their correlation with sex, age, and body size usually cause methodological problems in phenetic investigations. Based on data on four mammalian species (Microtus oeconomus, M. limnophilus, Lepus europaeus, Capreolus capreolus) studied by the author, and on data from the literature these problems were analyzed. Both the number and the coefficients of intercor- relations among traits were found to depend on sample sizes of individuals examined. They were larger in populations with progressive and faster body growth. The number of traits related to sex increased significantly with sex dimorphism across mammalian species. Age dependence of traits did not show a regular pattern within and among species. These results are discussed as to their implications for estimating morphological differentiation within and among populations.
The Superb Lyrebird is a sexually dimorphic passerine that although is not considered endangered, it has been declining in population size since the 1940s due primarily to urban development. Recent reports suggest that lyrebirds may be threatened by chlamydial infection. We studied levels of faecal infection by two microparasites in lyrebirds: Chlamydophila psittaci and Escherichia coli in the Sherbrooke Forest, south-eastern Australia. Fresh faecal samples were obtained from 33 lyrebirds (15 adult females, 13 adult males and 5 juveniles) — estimated of 27.5% of the population, all of them tested negative to Ch. psittaci. E. coli prevalence was compared between adult males and females and no difference was found. This result is expected, for instance, if E. coli is sexually transmitted and lyrebirds are promiscuous. Trends for juveniles to be more parasitized than adults were detected, but they were statistically not significant. Behavioural analyses of video footage indicate that E. coli infected birds did not allocate more or less time to any of the activities considered than did non infected birds. This might suggest that E. coli infection in lyrebirds is relatively benign, and behavioural effects may thus be subtle. No significant differences were found in specific measurements of foraging behaviour but non infected birds tended to scratch more frequently than infected birds.
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